The use of video projectors designed specifically for home cinema applications is becoming more widespread in homes but such video projectors need a reflective projection sheet that is adapted to front projection. The projection sheet must thus be non-translucent without the slightest fold, and under the highest possible tension and until now these requirements have made it impossible to fold such an opaque reflective sheet without leaving fold marks that spoil the quality of the front projected image from such a video projector.
Front projection sheets for video projectors are either rolled along their long dimension within motor-driven or manual roll-up cases or else they are tensioned on a fixed frame of length equal to the base of the screen. That occupies a very large horizontal space on the wall of a home where such a sheet has been installed.
Some projection sheets are improved by a tensioning device seeking to make the sheets more plane while they are in use. However the tensioning device further increases the horizontal size of such screens, and on the contrary makes it even more difficult to integrate them discreetly on the wall of a home.
Some devices enable a back projection screen to be folded so as to make it transportable and capable of being installed quickly in front of a professional or school auditorium, however those devices apply only to translucent screens for projection from behind, and not to reflective screens for front projection. Thus, devices of that type exist only for professional or school applications and they are not sought out by people seeking to set up a private home cinema based on a video projector.
Other devices enable a support or stand for a screen to be folded, but not the reflective sheet for front projection itself.
Other devices enable a translucent screen to be folded into a box for placing on a horizontal support during traveling professional or school utilizations, but no device enables a reflective sheet to be integrated and folded behind wall decoration for home use, without leading to irreversible damage to the sheet.
The following patent documents illustrate such devices and are representative of the present state of the art:                EP-A2-0 085 527 relating to the construction of a projection screen;        EP-A1-0 631 174, describing a giant screen with a hinge for an open air showing;        WO 97/09853 relating to presentation screens fitted with loudspeakers;        EP-A1-1 233 300 relating to a projection screen with a support;        WO 03/100519, relating to a self-contained screen that is unfolded manually;        U.S. Pat. No. 6,466,369, relating to a portable display device with a folding screen; and        WO 2004/027515 describing a wall screen that can be rolled up and unrolled.        